ok, so I've been running current64 and I thought I understood what I was doing with the kernel updates, but this is the second time I've screwed this up, and I'm asking for help in what I'm doing wrong.

If there's a kernel update in current, I install the new kernel, then copy the huge kernel into /boot/efi/EFI/Slackware. I have an elilo stanza to boot a huge kernel as well as the generic one, so shouldn't a reboot load the new kernel and let me make a new initrd for a new generic kernel with the mkinitrd script?

I copy the kernel over, let elilo try to load the new huge kernel, and I get a kernel panic. I can still load the old generic kernel, but what step am I missing for booting with the new huge kernel?

Why not make the new initrd before you reboot?

Right now, I'm upgrading from 4.4.8 to 4.4.9. I'll run the command...
...before I run either lilo or grub-mkconfig. (If I'm using lilo on the target box, I'll also have to update the lilo stanza prior to running lilo.)

I have no experience with elilo, but I don't know why it would differ to a large degree.

Please post your elilo.conf. It should include a line for your initrd if you use a generic kernel.

Maybe, just run eliloconfig again (but when asked, keep the old entries just in case). It should find the kernel referred to as vmlinuz in /boot and /boot/initrd.gz

Also, it is not clear if you boot using your firmware's boot menu or through elilo.

^^

Thanks for the tip. For some reason, it never occurred to me to simply run the mkinitrd script with the kernel version before I rebooted. I'll certainly give that a try the next time.

^ Here's my elilo.conf:

elilo.conf, vmlinuz, and vmlinuz-generic are all copied to /boot/efi/EFI/Slackware. I did it that way since the installer puts the huge kernel in that directory as vmlinuz. That's why I thought I should just be able to copy the new huge kernel to that directory as vmlinuz, reboot into it and then run the mkinitrd script. But as soon as I did, the huge kernel panicked, and that was as far as I got.

Thanks to the both of you for your input. I thought I was doing this the right way, but it's obvious that there's something simple that I still don't get.

You need to also copy there initrd.img, else elilo won't find it. Also I would increase the timeout a bit as a value of 30 gives just 3 seconds.

^ I don't have that file. Not in /boot, not in /boot/efi/EFI/Slackware, and a locate doesn't find it either.

Then booting the generic kernel is deemed to fail, as it has no built in support for the file system needed to mount / (the root directory). Read /boot/README.initrd.

^ I get that part. But booting a generic kernel actually comes after the part I'm having trouble with. Let me try again.

PV updates the kernel from 4.4.8 to 4.4.9
I install the new kernel, leaving the old one in place as well.
I then copy vmlinuz-huge-4.4.9 to /boot/efi/EFI/Slackware as vmlinuz.

Reboot -> kernel panic -> revert to old kernel and scratch my head.

My question is why doesn't copying the new huge kernel to efi/EFI/Slackware let me boot into the new huge kernel so I can make a new initrd? It seems like it should, so I'm asking if there's a step that I'm missing between copying the new huge kernel and rebooting. I solve that, the rest would take care of itself.

Are you sure it's the huge kernel that panics, not the generic? (I see default is generic in your elilo.conf)
Any idea what does the panic message look like, could you take a pic?

I have no idea, but is necesary to run elilo for the same reasons it is necessary to run lilo after making a change?

Not necessary

OT: Boy, I can't wait to get a non-BIOS motherboard. They sound like a lot of fun.

Yeah, it's the huge that panics. The default in my elilo.conf is generic, but I have it set to prompt. I can hit the tab key and a list of installed kernels pops up and I can pick one, and when I select the new huge kernel, it panics.

I'll try to get some kind of screenie of the panic, but it locks up tight and the only way out is a hard boot. And I don't know enough about kernel panics to describe it with any useful info.

Can you make a picture of the screen, upload it somewhere and provide a link?

Thanks all for the input, but RC's command in post #2 worked a treat. I booted into the old generic-kernel, created the new initrd.gz, copied it to /boot/efi/EFI/Slackware, copied over the new generic-kernel, and I was back in business.

I don't know why what I tried the first time didn't work, as I still think it should have, but now that I have a process that works, I'm not going to sweat it, so I marked this thread solved.

I did download a new current image with the 4.4.9 kernel and installed it in another partition, and I can boot from that huge kernel, so apparently the installer is doing something that I didn't. I'm going to have to take a look at that code and see if I can find what it's doing that I didn't.

Thanks again for the replies.